mirror/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2026-01-20 22:35:24 +00:00
Code Issues Packages Projects Releases Wiki Activity

std.Progress: fix race assertion failure

Browse Source 
A node may be freed during the execution of this loop, causing there to
be a parent reference to a nonexistent node. Without this assignment,
this would lead to the map entry containing stale data. By assigning
none, the child node with the bad parent pointer will be harmlessly
omitted from the tree.

Closes #20262
This commit is contained in:
Andrew Kelley 2024-06-11 15:15:21 -07:00
parent d9bd34fd05
commit 4b776ae441
1 changed files with 14 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
lib/std/Progress.zig
View File

@ -734,7 +734,7 @@ const Serialized = struct {
const Buffer = struct {
parents: [node_storage_buffer_len]Node.Parent,
storage: [node_storage_buffer_len]Node.Storage,
map: [node_storage_buffer_len]Node.Index,
map: [node_storage_buffer_len]Node.OptionalIndex,
parents_copy: [node_storage_buffer_len]Node.Parent,
storage_copy: [node_storage_buffer_len]Node.Storage,
@ -753,9 +753,11 @@ fn serialize(serialized_buffer: *Serialized.Buffer) Serialized {
// Iterate all of the nodes and construct a serializable copy of the state that can be examined
// without atomics.
const end_index = @atomicLoad(u32, &global_progress.node_end_index, .monotonic);
const node_parents = global_progress.node_parents[0..end_index];
const node_storage = global_progress.node_storage[0..end_index];
for (node_parents, node_storage, 0..) |*parent_ptr, *storage_ptr, i| {
for (
global_progress.node_parents[0..end_index],
global_progress.node_storage[0..end_index],
serialized_buffer.map[0..end_index],
) |*parent_ptr, *storage_ptr, *map| {
var begin_parent = @atomicLoad(Node.Parent, parent_ptr, .acquire);
while (begin_parent != .unused) {
const dest_storage = &serialized_buffer.storage[serialized_len];
@ -766,12 +768,19 @@ fn serialize(serialized_buffer: *Serialized.Buffer) Serialized {
if (begin_parent == end_parent) {
any_ipc = any_ipc or (dest_storage.getIpcFd() != null);
serialized_buffer.parents[serialized_len] = begin_parent;
serialized_buffer.map[i] = @enumFromInt(serialized_len);
map.* = @enumFromInt(serialized_len);
serialized_len += 1;
break;
}
begin_parent = end_parent;
} else {
// A node may be freed during the execution of this loop, causing
// there to be a parent reference to a nonexistent node. Without
// this assignment, this would lead to the map entry containing
// stale data. By assigning none, the child node with the bad
// parent pointer will be harmlessly omitted from the tree.
map.* = .none;
}
}